[flueedo]

My suggestion is that you ask this question at security.stackexchange.com , also browse the website for similar questions already answered.

My answer: A laptop usually can trivially be taken apart completely and then put back together without any signs of the operation remaining, internally or externally. Same thing with smartphones. Checking BIOS integrity usually isn't possible without specialised physical tools.

[ds9]

Thank you! Found this so far: http://security.stackexchange.com/questions/7203/checking-if... - and it's not very encouraging. The answers there assume that the now-owner has access to a "clean" state of the machine to compare a later condition with - but the problem situation, and the reality for everyone today, is evaluating the condition when it's first received.